Led Zeppelin is the most influential band in the history of rock'n'roll. Critics would like to believe it is the Beatles, but the Beatles' influence is mostly felt in quirky ensembles like Squeeze, the Vines and Muse, or gaseous, pontifical conglomerations like the Electric Light Orchestra. The influence of the Fab Four is rarely heard elsewhere, because the eclectic Beatles played in many styles and tempos, whereas rock bands only play the fast song and the slow song. Moreover, rock bands do not record songs like Rocky Raccoon or Mr Moonlight. Their fans would lynch them.

By contrast, the influence of Led Zeppelin is felt everywhere, from Guns 'N Roses to Pearl Jam to the Foo Fighters to Spinal Tap. The charismatic vocalist, preferably blonde and vaguely angelic - in the sense that Lucifer was angelic - accompanied by the emaciated guitar hero, assisted by the leaden-footed drummer and the sturdy but invisible bassist, is the prototype for virtually every rock band that has come into existence in the past 40 years. No strangers to drugs or the police, Zeppelin personally spawned several of rock music's most beloved cliches - the TVs hurled out the hotel window, the groupie molested with shark fragments, the drummer who goes out to the pub for a drink and never comes back, the concert swag swiped from the hotel safe - engaging in the kind of heroically stupid, self-destructive behavior that dainty alternative bands eschew because it isn't fair to women and degrades the ecosystem.

White kids in the 70s, 80s and even the 90s did not grow up wanting to be George Harrison or Eric Clapton or Stevie Vai or Slash; they grew up wanting to be Jimmy Page. True, they would have liked to develop Keith Richards' swagger, and perhaps borrowed Slash's hat for the evening, but they didn't want to play guitar like those guys. They wanted to play like Jimmy Page. Even Clapton would like to play like Jimmy Page. Dream on, Slowhand.

Formed - almost by committee - in 1968, Led Zeppelin was initially viewed by rock cognoscenti as ham-fisted, pretentious and ridiculous: all that post-Wagnerian "Hammer of the Gods" malarkey certainly didn't help. Unlike the tuneful Rolling Stones, whose major influence was Chuck Berry, Led Zeppelin were less interested in songs than in sound, playing their instruments like assault weapons. Eventually they wore down most of their detractors by virtue of their undeniable brilliance, even though the charges of being ham-fisted and pretentious and ridiculous were not unfounded, and L'Affaire Mudshark was never really forgotten.

Nowhere is the band's heavily metallic, neo-Druidic, phantasmagoric Runic silliness on better display than in Stairway to Heaven. Stairway to Heaven, like Satisfaction or Layla or Deutschland Uber Alles is a song that has been around for so long and played so many times and been the object of so much ribbing that one can no longer imagine a society that antedated it. The song is the musical equivalent of Granny's sitting room; it is impossible to conjure up a world that did not include that faded Monet print, that cracked ottoman, or those appalling drapes. Much less Granny.

Stairway to Heaven, the most requested and performed song in the history of American "progressive" radio, was never released as a single stateside. Composed on the road by Page and Plant, it was recorded in London in the winter of 1970-71 and first performed in Belfast that March to an audience that wanted to hear something else, and had probably taken so many drugs that they thought they were. The song gradually took on mythical stature as Led Zeppelin evolved into the biggest name in rock music, and ultimately was institutionalised as their final, pre-encore number in most performances, even though the band started to get sick of it.

The enigmatic lyrics concern a wealthy woman who is trying to buy her way into the Kingdom of Heaven, and may not succeed, though usually this sort of trans-celestial financial gambit works. Many theories have been advanced to explain the lyrics, though mostly by shut-ins. As the song gained traction in the United States, the usual cavalcade of Christian ding-dongs began spreading rumors that when played backwards, it contained an apocalyptic Satanic message: Get your kicks on Route 666.

This suggested that the song played backwards might actually make sense, which the song played forward did not. For Zeppelin fans, this would have wrecked everything. The rumor was fueled in part by Plant's admission that the lyrics had simply come to him from whereof he knew not, though why this place would be Hell as opposed to Limbo, Valhalla or Stroud is not clear.

The rumor was officially investigated by a California congressional committee in the 1970s when Ronald Reagan was still governor of that unpredictable state. The committee, despite the use of the finest technology available, could find no evidence directly linking Satan with the composition or recording of the song, though allegations that he may have done post-production work on Rod Stewart's cover of People Get Ready with Jeff Beck have persisted to this day. This is not only because Page replaced Beck in the Yardbirds, nor because Led Zeppelin was a clone of Beck's short-lived, eponymous supergroup - whose lead singer was Stewart - but because Stewart used to fly all the way from Los Angeles to play football with the Highgate Redwings, a semi-pro team whose home pitch is not far from the graveyard where the satanic Karl Marx is buried, and whose lineup included my demonic brother-in-law Max.

Also, the opening chords to the Led Zeppelin song are lifted from Spirits instrumental Taurus, which was written by a native of Los Angeles named Randy California. So you can see how this all fits together.

Stairway to Heaven, the subject of good-natured joshing in the film Wayne's World, has been recorded in irreverent or parodic form by many performers, ranging from Frank Zappa to Dolly Parton to Pat Boone to the Leningrad Cowboys (ably assisted by the Red Army Chorus). Zappa, a legendary iconoclast greatly influenced by the composers Pierre Boulez and Edgar Varese, spent his entire career sneering at bands like Led Zeppelin, even though his own solos were Brand X retreads of Page's exquisite work and he never wrote a song one tenth as good as Kashmir. Neither Zappa nor his snooty fans ever understood that smart guys finish last in rock'n'roll, where brains and formal training merely get in the way. Stick with the mud sharks and you'll do fine. By the way, if you read this sentence backwards, it spells out the message: "Zappa sucks. Signed: Satan."